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crypto: Add generic 8-bit carry-less multiply routines
Reviewed-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
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/* | ||
* Carry-less multiply operations. | ||
* SPDX-License-Identifier: GPL-2.0-or-later | ||
* | ||
* Copyright (C) 2023 Linaro, Ltd. | ||
*/ | ||
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#include "qemu/osdep.h" | ||
#include "crypto/clmul.h" | ||
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uint64_t clmul_8x8_low(uint64_t n, uint64_t m) | ||
{ | ||
uint64_t r = 0; | ||
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for (int i = 0; i < 8; ++i) { | ||
uint64_t mask = (n & 0x0101010101010101ull) * 0xff; | ||
r ^= m & mask; | ||
m = (m << 1) & 0xfefefefefefefefeull; | ||
n >>= 1; | ||
} | ||
return r; | ||
} | ||
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static uint64_t clmul_8x4_even_int(uint64_t n, uint64_t m) | ||
{ | ||
uint64_t r = 0; | ||
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for (int i = 0; i < 8; ++i) { | ||
uint64_t mask = (n & 0x0001000100010001ull) * 0xffff; | ||
r ^= m & mask; | ||
n >>= 1; | ||
m <<= 1; | ||
} | ||
return r; | ||
} | ||
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uint64_t clmul_8x4_even(uint64_t n, uint64_t m) | ||
{ | ||
n &= 0x00ff00ff00ff00ffull; | ||
m &= 0x00ff00ff00ff00ffull; | ||
return clmul_8x4_even_int(n, m); | ||
} | ||
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uint64_t clmul_8x4_odd(uint64_t n, uint64_t m) | ||
{ | ||
return clmul_8x4_even(n >> 8, m >> 8); | ||
} | ||
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static uint64_t unpack_8_to_16(uint64_t x) | ||
{ | ||
return (x & 0x000000ff) | ||
| ((x & 0x0000ff00) << 8) | ||
| ((x & 0x00ff0000) << 16) | ||
| ((x & 0xff000000) << 24); | ||
} | ||
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uint64_t clmul_8x4_packed(uint32_t n, uint32_t m) | ||
{ | ||
return clmul_8x4_even_int(unpack_8_to_16(n), unpack_8_to_16(m)); | ||
} |
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/* | ||
* Carry-less multiply operations. | ||
* SPDX-License-Identifier: GPL-2.0-or-later | ||
* | ||
* Copyright (C) 2023 Linaro, Ltd. | ||
*/ | ||
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#ifndef CRYPTO_CLMUL_H | ||
#define CRYPTO_CLMUL_H | ||
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/** | ||
* clmul_8x8_low: | ||
* | ||
* Perform eight 8x8->8 carry-less multiplies. | ||
*/ | ||
uint64_t clmul_8x8_low(uint64_t, uint64_t); | ||
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/** | ||
* clmul_8x4_even: | ||
* | ||
* Perform four 8x8->16 carry-less multiplies. | ||
* The odd bytes of the inputs are ignored. | ||
*/ | ||
uint64_t clmul_8x4_even(uint64_t, uint64_t); | ||
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/** | ||
* clmul_8x4_odd: | ||
* | ||
* Perform four 8x8->16 carry-less multiplies. | ||
* The even bytes of the inputs are ignored. | ||
*/ | ||
uint64_t clmul_8x4_odd(uint64_t, uint64_t); | ||
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/** | ||
* clmul_8x4_packed: | ||
* | ||
* Perform four 8x8->16 carry-less multiplies. | ||
*/ | ||
uint64_t clmul_8x4_packed(uint32_t, uint32_t); | ||
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#endif /* CRYPTO_CLMUL_H */ |